High Level Design
EE Senior Design
November 1, 2007
Mike Clarke
Brendan Hennessy
Evan Lintz
Kevin Carr Payne
I. INTRODUCTION
Every year, thousands of injuries are reported due to fireworks. The goal of our project is to prevent this, all the while keeping everyday firework displays fun and easy to put on. This document will provide a high level overview of our project, including the system requirements, high level design decisions, and major component cost decisions.
II. PROBLEM STATEMENT
According to the Center for Disease Control and Prevention, four people were killed and over 10,000 people had to be taken to the emergency room on fireworks related injuries just last year. Five percent of these injuries required hospitalization. Over half of these injuries are burn related and affect mostly the eyes, head, and hands. Also, children ages 10-14 are those most commonly injured. It is obvious that there are serious dangers when using fireworks that can lead to permanent injuries such as blindness and scars. In all, the CDC cited various factors in their report on fireworks safety regarding how these injuries occur. The main factors for injuries include: availability of firework, type, being too close, lack of physical coordination, curiosity, and experimentation. Our project will provide a solution for the factors of being too close and lack of physical coordination that can result in fireworks injuries. Typically, one is forced to simply light an unreliable fuse and run as fast as one can to get a safe distance.
Another problem we will address is that putting on an at home fireworks show is nearly impossible. One must be forced to light one firework at a time which could lead to haste and an increased chance of injury. Additionally, the person will not be able to sit back and enjoy the fireworks show.
III. SYSTEM DESCRIPTION AND BLOCK DIAGRAM
Our senior design project will provide a solution to making fireworks safer. It will also provide an interface so as to enable one to safely put on a fireworks display. The logical functions of our proposed solution are summarized below:
Fireworks Safety: The main cause of fireworks incidents that we are going to eliminate are being too close and lacking physical coordination. Oftentimes fireworks are very unpredictable. The fuse for instance may be short or runs too fast – leading to an ignition before the individual is a safe distance away. In all, the individual has to simply light the fuse, hope they can get out of the way, and run back a safe distance. We will eliminate having to do this through a remote ignition interface. By creating this safety device for fireworks, we hope to provide a safe and effective way for lighting and launching fireworks.
The first feature of this device will be the remote launch and ignition. In order to launch a firework from a distance, an electrical igniter will be necessary. This igniter will take advantage of the heat generated when a current flows through a piece of metal. We will create a heat element to ignite the firework fuse from a safe distance. Since we will be firing a multitude of fireworks specifically timed, we will need to design a sophisticated remote launching set-up. We plan to incorporate three firework modules that will be loaded with three different kinds of fireworks, mortars, rockets, and fountains. These modules will be controlled wirelessly by a computer programmed transmitter. This will allow for the safe, effective launch of fireworks.
Another feature will be the sensors on the bottom of mortar tubes. This will allow the system to know if a mortar fires, but doesn’t exit the tube. This will ensure one does not peer over a tube after the show that may hold a “dud” and advise one to approach the tube with caution. LEDs will tell the operator whether a tube is safe to approach.
The emergency stop button feature is just what the name implies. On the fireworks control device, there will be an automatic stop that clears the rest of the fireworks ignitions and allows one to approach the launch platform if something goes wrong. This will basically be a simple interrupt.
The test mode function will send small currents through the remote ignition device to ensure no open circuits exist and everything is wired correctly. This will ensure that all fireworks light and that everything is in working order before the launch. A clamp connected to the igniter will tell if a fuse is placed inside the heating element. This will allow for the platform to count how many fireworks have been loaded and into which tubes they have been loaded.
The safety platform function is basically just a sturdy stand for the fireworks. We hope to be launching multiple fireworks at once, so the stand will provide the tube and supports for all launching needs.
Firework Show Design: By being able to control the launch sequence of various fireworks, we will correct this problem and allow the user to have complete control over the firework display. This will mostly be seen via a computer.
The layout of the fireworks in the field will provide a spatial display for where everything is being launched. This will allow one to choose what type of firework is launched when. For instance, if one has fountain type and mortar type fireworks, one would not like all the mortars to go off at once or at one specific location, but varied throughout the show. Being able to see the layout will allow the user to choose the launch sequence. This will be designed on a computer.
The next function will be control over the launch sequence. After one shows where the types of fireworks are located in the field, a time sequence can be established for when a firework is to go off. For example, the mortars mentioned in the previous paragraph will go off at various intervals instead of all at once.
Another feature but a lofty goal is to have a preview mode. This may require a lot of programming knowledge but it would be nice to have a preview mode to get a sense of the timing and location for how the fireworks display will look.
Another key element of firework displays is to have it be coordinated to music. By giving the everyday consumer the ability to load music and have it synchronized with the fireworks launch sequence, the entire fireworks experience will be greatly enhanced.
Below is the block diagram of our system. The next page shows preliminary diagrams of a firework platform and the three different types of launchers that will accommodate three kinds of fireworks.
IV. SYSTEM REQUIREMENTS
IV.I OVERALL SYSTEM REQUIREMENTS
Our system will:
· Implement critical safety features to protect users from fireworks
o LED illumination on tubes to communicate state of system to operator
o Provide key security mechanism to prevent accidental launch during loading of fireworks
o Place large, well-marked emergency stop button on top of base station to cut execution of a launch sequence
o Use wireless protocol to communicate with the launchers from a safe distance of at least 200 feet
o Construct a durable and secure base from which to launch fireworks
· Display exhilarating fireworks shows for user enjoyment
o Usability
§ Launch fireworks with reusable electronic ignition device
§ Use software interface to preprogram base station with timed launch sequence
§ Launching does not require USB connection with laptop or PC
§ Preview fireworks display on computer prior to physical launch
§ Initiate launch sequence with simple press of “Go” button with key inserted
§ Data describing the available fireworks is displayed in software application
§ Rechargeable battery for both base station and launching
o Wireless communication
§ Base station sends launch command for a specific firework type
§ Launch pods receives command and launches only if the specific type of firework requested matches the type of launch pod (assembles
§ Launch pods transmit information that identifies the type and quantity of fireworks currently loaded in the tubes
§ Launch pod logs error in base station but does not stop launch sequence if an attempt is made to launch a firework after that quantity has been expended
§ Base station displays on LCD screen which launch pods are currently connected
§ Assume that only unique launch pods are available in mesh network (mortar pod, bottle rocket pod, fountain pod)
IV.II SUBSYSTEM REQUIREMENTS
· Computer Software Front-end
o Easy-to-use software, written in VB.net, lets user enter when to launch a specific firework, at a specific time (or interval)
o Interface allows user to view what types of fireworks are available as well as quantities on hand
o Output of program is text-based data file that is interpreted by the base station during the launch sequence (format should be firework type, launch time)
· USB Interface between Computer and Base Station
o Auto-detect and open software application automatically
o Store / load data file based on application command
· Base Station
o Receive information from launcher pods (firework type, firework quantity loaded in pod, whether system is properly connected)
o Illuminate a red LED if a tube is loaded with a firework
o Illuminate a green LED If the pyrotechnic has launched (touch sensor and fuse sensor both indicate that firework has launched successfully)
o Illuminate an orange warning LED if a firework is loaded but the fuse is improperly connected
o Emergency stop button that halts launch of fireworks immediately
o Key that only allows execution when the key is turned to “GO” position
o Send launch command at a specified time to a specific firework type
· Wireless Communication Protocol
o Communicate with > 200ft. range outdoors
o Facilitate sending and receiving between base station and pods
o Base station communicates with any specific pod
o Pod communicates with base station
o Identification of transmitting pod with each message sent
· Fireworks Pod
o Intelligence to recognize when firework is loaded
o Ability to launch random available firework on command
o Connect to MUX in order to handle limited # of output ports
o Transmit back to base station when out of fireworks, on connectivity error, type of firework loaded in pod
· Electronic Ignition
o Coiled heat element to ignite fuse
o Reusable for multiple ignitions
o Capable of receiving low level current signal to determine if connected properly
· Launch Pad
o Plywood base which PVC pipes will sit on
o Base of pad will be staked to ground to ensure stability
o Position for battery source and receiver circuitry
IV.III FUTURE ENHANCEMENT REQUIREMENTS
· Motion sensor (Passive Infrared Sensor)
o Shut down launch of fireworks if motion detected within 20 ft of launch pad
· Synchronization with music
· Motors to adjust direction of launch to the wind direction
· Buoyant Firework modules for water based firework shows
V. HIGH LEVEL DESIGN DECISIONS
Microcontroller Selection
Our design requires a microcontroller to be present in both the base station and inside each transceiver pod. For simplicity of programming and implementation, our team elected to use the same microcontroller for both applications (even though it will have substantially more functionality than necessary when used in the pod). When examining microcontrollers, the team considered several important characteristics of an “ideal” microcontroller:
· USB Interface onboard microcontroller
By choosing a microcontroller with an onboard USB implementation, we determined that it would eliminate the need for extra hardware and streamline our implementation of the interface.
· Well-documented technical specifications of microcontroller
Thorough yet comprehensible documentation is essential for our team to understand the nuances of the microchip and take full advantage of its capabilities
· High availability of libraries and example applications
Extensive sample applications allow the team to focus on customization of existing solutions and to leverage the work of others in using the chip for our applications
· Low price point
Our team anticipates abusing and destroying multiple microchips in the process of testing and polishing the final prototype; as such, an economic chip provides us with freedom to experiment.
· Similarity to PIC18f4620
While several competitors manufacture chips that compete with Microchip’s devices, the tasks executed for class were performed exclusively with the PIC18 architecture. By choosing a microcontroller of the same architecture type, our team can leverage the knowledge already acquired with little to no modification
· Lots of processing horsepower, ports and features
A processor with excessive horsepower, ports and features provides ample room for our software to grow and expand without the need to choose an entirely different microcontroller.
Several processors were evaluated for how well they match up with these requirements:
Microchip PIC18F4550 / Cypress EZ-USB / Cypress enCoRe IIUSB Onboard / / X / X
Well-documented / / X / X
Libraries and examples /
Low price point / / X / X
Lots of horsepower / / X / X
Similarity to PIC18f4620 /
From this analysis, the PIC18F4550 represents the best choice for our particular project.
Wireless Communication
Our proposed solution outlines the use of one base station to communicate to multiple firework modules. To determine which one is right for our project, we first looked at the requirements of our system that needed to be met.